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Serum Creatinine (Creatinine Level)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of creatinine, a waste product from muscle metabolism, in your blood. It helps assess how well your kidneys are filtering blood.

Quick summary

["A creatinine test helps check kidney function by measuring waste in your blood."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
23287-6
Short code
M myc my sc Ab Ser Ql IA
Synonyms
M myc my sc Ab Ser Ql IA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Matters

Creatinine is a byproduct of muscle breakdown and is normally filtered out by your kidneys. High levels can indicate kidney problems, while low levels might suggest dehydration or muscle loss. This test is often used alongside other measures to monitor kidney health, especially in people with diabetes, high blood pressure, or a history of kidney issues.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re on dialysis or have had recent kidney procedures, your doctor may advise specific timing.

How the Test Works

Blood is drawn and sent to a lab, where it’s analyzed to measure creatinine levels. The test is quick and typically done in a doctor’s office or lab setting.

What the Results Mean

Results are usually reported in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). Your doctor will compare your results to your baseline or to general reference ranges to determine if your kidneys are working as expected. Abnormal results may prompt further testing or follow-up.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Creatinine

Frequently asked questions

How often should I get this test?
The frequency depends on your health. People with kidney disease, diabetes, or high blood pressure may need this test more often, often every few months or annually. Healthy adults may only need it if they have risk factors like a family history of kidney problems or obesity.
What if my results are high?
High creatinine levels may signal reduced kidney function. Your doctor could recommend lifestyle changes (like hydration, diet adjustments), medications, or further tests to investigate the cause, such as chronic kidney disease or dehydration.
Can diet affect this test?
Yes, diet can influence creatinine levels. High-protein foods or muscle breakdown (e.g., from intense exercise) may temporarily raise levels. Avoiding large meals or protein-rich foods before the test can help ensure accurate results.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy